In the distribution of liquid beverages, it is common to use generally cylindrical metal tanks each having an upper end wall with a removable closure and two upwardly projecting valve plugs. The valve plugs form parts of quick-connect couplings which releasably connect corresponding flexible hoses to the plugs for pressurizing the tank and for supplying the liquid in the tank to a liquid dispenser. Sometimes the valve plugs are protected by sanitary dust caps, for example, as disclosed in U.S. Pat. No. 4,318,495 which issued to the assignee of the present invention. In addition to the sanitary dust caps, it is sometimes desirable to provide the cap with tamper-evident means which provide an indication if the cap has been removed, for example, as disclosed in U.S. Pat. No. 4,095,713. However, the tamper-evident cap disclosed in the latter patent has several openings in the upper portion of the cap, and the openings prevent the cap from forming a sanitary cover for the valve plug.